It's possible to drag and drop music file directly on playlist pane of Jaangle. However, it sometime seems not to work properly. You can read and post more detail about this problem from here: viewtopic.php?f=3&t=891

There seems to be a built in Drag and Drop but as far as I can tell it only works with in Farmanager. The drgndrop addin allows dragging to desktop and back but unfortunately this does not seem to work in the 64bit version.